This invention relates to a system for tracking personnel and assets over an extended area composed of one or more sub-areas which are monitored by sub-area monitoring systems. The sub-area monitoring systems communicate with and update location databases resident on a common central server. Clients communicate with and access the databases of the central server via an Internet web browser interface.
Location and tracking systems using object tags, a plurality of receivers located at known locations and a central computer are well known in the art. The tags periodically transmit a unique ID signal which is received by the receivers and the central processor combines the receiver location with the tag ID to determine the location of the object associated with the tag. However, these systems have several limitations. Location data maintained by the central processor has limited accessibility from locations other than the central processor. All location data is maintained by the central processor. Any location monitoring devices that send location data to the central processor must be specifically designed to work with the central processor, and must be like all the other location monitoring devices connected to the central processor. All of the location data must be sent to the central processor and anytime communication with the central processor is lost the location data collected by the disconnected location monitoring devices is inaccessible. The central processor receives location updates but does not forward location data to other monitoring systems.
An illustrated embodiment of the present invention includes a central location database that can be accessed from any computer with network access to the central server through Intranet or Internet using a standard web browser interface. The web browser interface is illustratively created using a Microsoft technology called Active Server Pages and the programming language VBScript. Active Server Pages allow the creation of dynamic web pages which are tailored according to the requests of the client queries. The dynamic server pages are interpreted by the web browser to provide virtually complete access to the location databases and other databases maintained on the central server. Any computer with communications network access to the central server and supporting a web browser interface can access the location data and other data stored on the central server.
The illustrated embodiment of the present invention allows the tracking and locating of objects over a large area by combining the object transmissions received over multiple sub-areas which are monitored by autonomous monitoring systems interconnected through a communications network. Each location monitoring system sends the location updates to the central server over the communications network. The central server can maintain location data for a large area by receiving location updates over several sub-areas which each have a location monitoring system tracking object tags in their particular sub-area. The area and sub-areas could be a building and its floors, a campus and its buildings, or several campuses and the floors of each of the buildings on each of the campuses. The sub-area monitoring systems only have to be able to track the same tags and have access to the central server over a communications network for a client connected to the central server to obtain location information on an object anywhere in the awareness area.
The illustrated embodiment of the present invention supports locating and tracking over the entire area using both dependent locating and tracking system, locating and tracking systems which depend upon the central database to store location data and to respond to database queries, and independent locating and tracking systems, locating and tracking systems which forward location data to the central server as well as maintaining local sub-area location databases. Each of the sub-area monitoring systems can either send all data to the central server for recording, a dependent monitoring system, or have a local database for objects assigned to the local sub-area and also send location updates to the central server, an independent monitoring system. If either monitoring system loses communication with the central server it will store location updates to transmit when communication is restored. An independent monitoring system will continue to support local location queries for the objects assigned to its sub-area when communication is lost with the central server. The central server can also pass location updates and messages back to the independent monitoring systems. If an object assigned to sub-area A is in another sub-area monitored by the central server then location updates can be recorded at the central server and forwarded to sub-area A to keep the local database updated even when the objects are outside sub-area A. The independent monitoring system can also assign new tags to the sub-area and receive updates from anywhere monitored by the central server. However, when communication with the central server is lost only objects within the sub-area can be tracked.
Additional advantages and features of the invention are set forth in the description that follows, and will become apparent to those skilled in the art upon reviewing the drawings in connection with the following description.